Ventilation structure for engine compartment

Abstract

A ventilation structure of an engine compartment that houses an engine and is adjacent to a cooling fan that supplies cooling air to a heat exchanger in a form of a radiator is provided. A ventilation structure of the engine compartment includes: an exterior cover with which the engine and the cooling fan are covered; and a ventilation duct that includes an inner surface of the exterior cover, in which a first end of the ventilation duct is open in the engine compartment while a second end of the ventilation duct intercommunicates with a surrounding area of the cooling fan.

The invention claimed is: 
     
       1. A ventilation structure of an engine compartment that houses an engine and is adjacent to a cooling fan that supplies cooling air to a heat exchanger, the ventilation structure comprising:
 an exterior cover with which the engine and the cooling fan are covered; and 
 a ventilation duct comprising an inner surface of the exterior cover, 
 wherein: 
 the cooling fan is rotated in a fan shroud with which a surrounding area of the cooling fan is covered, 
 the fan shroud is housed in a frame such that a periphery of the fan shroud is surrounded by the frame, 
 the frame comprises a pair of vertical frames extending in a vertical direction and a horizontal frame disposed between upper ends of the vertical frames, at least one of the vertical frames comprising a first communication opening, and the horizontal frame comprising a second communication opening, 
 the fan shroud comprises a third communication opening, 
 a first end of the ventilation duct is open in the engine compartment, and 
 a second end of the ventilation duct intercommunicates with the surrounding area of the cooling fan through the first, second, and third communication openings. 
 
     
     
       2. The ventilation structure of the engine compartment according to  claim 1 , wherein the ventilation duct comprises an air passage defined by the inner surface of the exterior cover and a reinforcing member attached to the inner surface of the exterior cover. 
     
     
       3. The ventilation structure of the engine compartment according to  claim 1 , further comprising:
 a heat exchanger compartment in which the heat exchanger is housed; and 
 a partitioning wall that is interposed between the heat exchanger compartment and the engine compartment to separate the heat exchanger compartment from the engine compartment. 
 
     
     
       4. The ventilation structure of the engine compartment according to  claim 1 , wherein:
 an exhaust gas aftertreatment device is provided in the engine compartment to purify exhaust gas discharged from the engine, and 
 the first end of the ventilation duct is open toward the exhaust gas aftertreatment device. 
 
     
     
       5. The ventilation structure of the engine compartment according to  claim 1 , wherein a cross-sectional area of an air passage of the ventilation duct is gradually decreased from the first end to the second end of the ventilation duct. 
     
     
       6. The ventilation structure of the engine compartment according to  claim 1 , wherein:
 the first communication opening is provided to an upper portion of each of the vertical frames, 
 the second communication opening is provided along a longitudinal direction of the horizontal frame, 
 the third communication opening is provided to an upper portion of the fan shroud, 
 the first communication opening faces a part of the third communication opening near the vertical frames, 
 the second communication opening faces the third communication opening, and 
 the second end of the ventilation duct intercommunicates with the surrounding area of the cooling fan through the first and third communication openings and through the second and third communication openings. 
 
     
     
       7. The ventilation structure of the engine compartment according to  claim 6 , wherein:
 the frame further comprises an intermediate frame disposed below the horizontal frame and between the vertical frames, 
 the intermediate frame comprises a fourth communication opening along a longitudinal direction thereof, 
 a part of the fourth communication opening near the vertical frames is located between the first communication opening and the part of the third communication opening near the vertical frames, the first communication opening facing the part of the third communication opening near the vertical frames through the part of the fourth communication opening near the vertical frames, 
 the fourth communication opening is located between the second and third communication openings, the second and third communication opening facing each other through the fourth communication opening, and 
 the second end of the ventilation duct intercommunicates with the surrounding area of the cooling fan through the first, third and fourth communication openings and through the second, third and fourth communication openings.